At the present time, Mars is a dry and cold planet. Surface ice is unstable for more than one season outside the polar regions, and the atmosphere is so cold or so dry that the presence of liquid water, never detected, is unlikely anywhere on the surface.

Methane has been reported by several observers as a short-lived trace gas in the martian atmosphere. If verified, this would be an extraordinary result. Is the evidence for methane extraordinary? In this talk, Dr. Kevin Zahnle will discuss why one should remain skeptical of Methane on Mars.

Space radiation poses significant risks to human explorers on extended missions beyond Low-Earth Orbit. Crews cannot be fully shielded against Galactic Cosmic Rays owing to their high energies, and sporadic but intense Solar Particle Events may also be hazardous when shielding is minimal. The physics underlying the transport of these particles through matter is reasonably well understood, but the biological response has large uncertainties. In this talk I will give an overview of these risks and describe NASA's ongoing program to mitigate them.

There are four worlds in our Solar System that have substantial atmospheres and observable surfaces: Venus, Earth, Mars, and Titan. The effects of an atmosphere interacting with a surface are clear: each of these planetary bodies has sand seas covering some fraction of its surface. Hidden within the morphology of these dunes lies a record of climate change that scientists are only beginning to understand.

Dr. Mahaffy is the Principle Investigator for the SAM analysis suite on Mars Science Laboratory Rover (Curiosity). An important goal of upcoming missions to Mars is to understand if life could have developed there. The task of the Sample Analysis at Mars (SAM) suite of instruments and the other Curiosity investigations is to move us steadily toward that goal with an assessment of the habitability of our neighboring planet through a series of chemical and geological measurements.

Life may have arisen independently on both Mars and Earth, may survive in subsurface niches on Mars, and may manifest itself via emission of gases such as methane. Microbes adapted to life in ice at low temperatures metabolize at a rate many orders of magnitude lower than their rate for exponential growth. Life in solid ice survives either until nutrients and bioelements are consumed or until alpha-particles from U and Th in the ice induce too many double-strand breaks.

One of the largest features on Mars is its hemispheric dichotomy: the difference in crater density, elevation (~4 km), and crustal thickness (~30 km) between the Northern Lowlands and the Southern Highlands. Recent impact cratering simulations show that the ~10,000 km diameter Lowlands can be formed by a single large impact. This impact size was common at the end of planetary accretion and falls in the planetary-scale impact size regime, in which the curvature and radial gravity of the planet are important. Dr.

Lakes are time capsules. On Earth, they are considered sentinels of climate change and may have played the same role on early Mars. Their basins capture the record of geological and environmental fluctuations over a wide range of temporal and spatial scales. Terrestrial lakes host a diversity of habitats where life’s adaptability can be pushed to the edge in often unstable environments. They preserve the evidence of ancient life as sedimentation rapidly entombs dead organisms and generates anoxic conditions favoring the formation of fossils.

The Haughton impact crater site on Devon Island, High Arctic, is one of the most Mars-like places on Earth. Since 1997, the Haughton-Mars Project (HMP) has been conducting science and exploration research at the site, and established the HMP Research Station, now the largest privately operated polar research station in the world. Geology and astrobiology investigations have led to the formulation of the “Mars, Always Cold, Sometimes Wet” Model. Dr.